


Not So Secrets

by Pepperminty (PeppermintPug)



Category: Big Hero 6 (2014)
Genre: Accidental Voyeurism, Implied/Incest, M/M, Masturbation, hidashi
Language: English
Status: Completed
Published: 2015-01-21
Updated: 2015-02-15
Packaged: 2018-03-08 12:00:20
Rating: Explicit
Warnings: Underage
Chapters: 2
Words: 2,780
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/3208397
Author URL: https://archiveofourown.org/users/PeppermintPug/pseuds/Pepperminty
Summary: <blockquote class="userstuff">
              <p>Hiro finds himself stuck when he discovers that Tadashi has beaten him home. With no other choice, he must wait for his brother to fall asleep before sneaking into bed.</p>
            </blockquote>





	1. Not So Secrets- Hiro

**Author's Note:**

> This is literally my first time writing a fic ever and it's been so long since I've last written anything at all, so please bare with me. I just fell so deep into Hidashi that I couldn't help myself from attempting to contribute to it. Of course, I claim no ownership of BH6 or any of its characters or parts.
> 
> Though this is technically the second fic I started, its the first I completed since its so short, as such I'm posting it first. Its unbeta'd, unless you count myself reading it over ten times plus. Please forgive any errors you might find. I might be posting the other one later when I have more buffer for it.
> 
> This fic is inspired by the actual comment from Hiro's journal, in which he mentions having a bedroom camera to catch Tadashi's reactions to his inventions.

Hiro knew about the GPS trackers in his jackets.

His brother hadn't exactly been sneaky about it; suddenly offering to wash them all at once for Hiro one day. He never mentioned anything about it though. Not only did they come in handy when things turned sour at a bot-fight, but hey, he had a couple secrets too.

The hidden camera installed on Tadashi's side of the room for instance. Hiro mainly used it to check if his brother was home before he snuck into the house after bot fighting— when he wasn't rescued by said brother that is. That, and to forever possess Tadashi's priceless reactions to his pranks. He'd never forget the look on the elder Hamada's face when he had rigged a few of the books to launch themselves off the shelves when the partition was opened. Hiro still laughed about it sometimes.

Tonight was one of those nights. The checking to see if Tadashi was already home ones, not the being rescued ones. 

Lifting the garage door just high enough so he could slip beneath it, Hiro shimmied into the makeshift lab. He slowly placed the door back down as he narrowed his eyes, trying to see through the darkness. Luckily, many of the electronics gave off a dim light even in sleep mode and it was just enough for him to avoid running into anything. 

He slid into the chair at the desk as he woke up the computer and typed in his pass code. The screen lit up and he lifted a hand to shield his eyes from the brightness of it. After his eyes adjusted he pulled up the camera's feed and gazed into the screen. 

Damn it.

Tadashi had beaten him home. He'd even left one of the lights on for the absent teen. That made things difficult. If he was awake anyways.

Hiro's eyes focused on his brother's sleeping frame— at least he looked to be sleeping. What hope he possessed was crushed when Tadashi shifted, sitting up to lean back against his headboard. Hiro whispered a silent curse as he crossed his arms. He'd have to wait until his brother went back to sleep to attempt any sneaking. He just prayed that the nerd wouldn't decide to head down to the lab to do any late night tinkering.

Grabbing a bag of gummy bears from his backpack, Hiro settled in for the wait.

———————————

Apparently Tadashi just wasn't sleepy. Or he was waiting to catch the younger Hamada trying to sneak in. Either way it'd been about 15 minutes since he'd sat up and Hiro had already polished off his first bag of gummy bears. He was about to tear open the second when something on the screen moved. He froze as he watched his brother on the screen, panic slowly rising in his chest. He wasn't getting up was he?

No- No. It didn't look like it. He was just... Wait. Was he-?

Hiro groped for the headphones he knew they kept somewhere on the desk, incapable of moving his eyes away from the screen before him. Once in his hand, he plugged them in and flipped the volume on. 

The first sound that hit his ears was the rustling of fabric, but as he increased the volume he could make out his brother's uneven breathing. It wasn't hard to put two and two together, and Hiro laughed quietly to himself.

So his brother _did_ have urges of those kind. The younger brother had never woken up in the middle of the night to _those_ kinds of noises, and Tadashi's showers were always rather short. As a result, he'd always thought Tadashi was above that kind of thing, or not even interested in it. Man, it was going to be difficult not to poke fun at him about it. He couldn't though, lest he clue Tadashi in on the camera's existence. 

Shaking his head with an amused grin, Hiro sat back and tried to contain his giggling. He should probably give his brother some privacy and cut the feed. Maybe he could just pass out on the couch in the lab. He could always claim he stayed up late working on Megabot or something. 

Hiro's finger was on the switch, ready to power everything down, when the mic picked up a low groan that sent a shiver down his spine. He bit his lip as his eyes slowly returned to the screen, his finger hesitating over the button. He could feel the guilty heat rising in his cheeks as he realized his brother had thrown back the covers, unknowingly exposing himself to the camera's lens. 

Hiro could just make out the silhouette of the fingers wrapped around Tadashi's cock in the dimly lit room. He was suddenly thankful for his brother's thoughtfulness in leaving the light on for him.

He cranked up the volume, downright _dirty_ sounds flooding his ears as he watched the elder Hamada pump his dick. He had no idea his nii-san could even make those noises. Hiro's mouth had gone dry before he realized his jaw had been hanging open.

He knew he really shouldn't be watching his brother pleasure himself, but it was... really hot. 

Like, _really, really_ hot.

He bit his lip again, stifling a groan as he palmed himself through his pants. God, he'd gotten so hard. With the headphones in it was almost like Tadashi was panting and moaning right in his ears and he squeezed his eyes shut as he shoved a hand in his shorts. He forced an eye open to watch the image of his brother displayed on the screen as he fondled himself, shoving the guilt he felt to the back of his mind.

He tried his best to match Tadashi's pace, but his brother's movements were slow and precise, nimble fingers sliding languidly up and down with purpose. He was obviously more patient and experienced than Hiro, whose strokes were quick and rough. Having only recently begun exploring his body in the past year, the teen was more interested in the conclusion than the experiment. When did Tadashi find the time, Hiro wondered briefly before another deep moan passed through the headphones. Hiro answered it with his own, choked back by a small sob.

Mumbling broken syllables of Tadashi's name, Hiro's free hand clutched the fabric of his shirt as his body hunched forward, his toes doing their best to curl inside the confinement of his shoes. He could feel his orgasm approaching, a few beads of sweat rolling down his face, and he fixed his eyes on the screen once more. 

That was when he heard it.

Well, technically he saw it on Tadashi's lips first, but he hadn't believed it until he heard it.

_"H-Hiro."_

Hearing his name whispered so passionately by his brother threw him over the edge and he came with a strangled cry, making a mess of his shorts. Half collapsing on the desk, he struggled to catch his breath as he heard Tadashi stifle a cry of his own. 

Damn. He really wanted to see the look on dear ole nii-san's face when he came. The younger Hamada chuckled breathlessly. How funny was it that both of them just got off on each other. 

Finally turning off the computer Hiro adjusted himself as he stood from the chair, wiping his sticky hand on the outside of his pants. It all needed to be washed now anyways. He stretched his pleasantly aching limbs before grabbing Megabot. Knowing Tadashi, if he hurried upstairs, his brother would likely be pretending to sleep. Feeling too guilty about what he'd just done to question Hiro's lateness. Until tomorrow at least.

Hiro grinned mischievously as he began to sneak upstairs. Whenever Tadashi did decide to ask, he wouldn't admit that he'd been out late bot fighting. 

But perhaps it was time to come clean about a different secret Hiro possessed.


	2. Not So Secrets- Tadashi

**Summary for the Chapter:**

> Tadashi tries to prank Hiro as revenge for the younger sneaking out and fails, possibly revealing his own secret.

**Notes for the Chapter:**

> Whoops I did a thing. 6 u 6  
> It's Dashi's turn to have a go.
> 
> Unbeta'd like always. I don't own BH6.

Of all the things Tadashi was, stupid was not one of them.

He knew his little brother knew of the GPS trackers he'd sewn into his jackets. How else could anyone explain it that he somehow always showed up exactly where his brother was when he snuck out to the bot-fights. Hiro never said anything about them, and in return Tadashi never said anything about the camera hiding in his side of the room.

He'd found it after tidying up the mess one of Hiro's pranks had made. For being a genius, Tadashi sometimes wondered if Hiro let his over confidence cloud his judgement. Why would you hide a camera on the same shelf of the books you rigged to throw themselves off of? Regardless, he'd left it in place instead of removing it. He had nothing to hide, and if recording his reactions to stupid jokes made Hiro happy then so be it.

After a rather successful day in the lab Tadashi had retired early, wishing his friends a good night. He checked his phone as he fastened his helmet and realized it wasn't as early as he thought it'd been. Quickly opening another app, he searched for his brother's whereabouts. Hiro didn't seem to be in a particularly dangerous area— in fact it wasn't far from the cafe. The fact that it was nearly midnight could only lead Tadashi to assume that Hiro was at a bot-fight. When would that knucklehead learn? 

The dot that represented the younger Hamada's position moved and Tadashi's heart started racing. His body jerked as he started the engine, and he fought the overwhelming urge to take off at top speed. He took a second to calm down before checking the app again. The dot-Hiro looked to be advancing in the direction of home. Considering it Hiro seemed to be traveling at a leisurely pace, the elder Hamada assumed he wasn't in any danger. 

He was about take off anyways to catch his brother, but he was tired and it didn't seem like Hiro needed rescuing. Heaving a heavy sigh, he settled for beating Hiro home instead.

It didn't take long to get home, and Tadashi had enough time to get settled in bed before checking his phone one last time. Hiro was almost home and Tadashi had half a mind to march down there to the garage and give him a stern talking to.

Or. He could play a little prank of his own. With a sly grin he turned on the light over Hiro's desk and dove under his covers, laying still while keeping an eye on the camera.

It wasn't long until the telltale light flickered on informing Tadashi that Hiro was watching, and he couldn't hold back the impish smile that spread across his face. He waited a minute or two before sitting up to recline against his headboard.

Truth be told, he'd planned on sitting up for the rest of the night, forcing Hiro to camp in the cold garage. Maybe it'd be so uncomfortable that he'd at least reconsider staying out so late. If it meant spending less time bot-fighting, Tadashi could consider it a win on his part. Or maybe Hiro would try to sneak upstairs anyways. Then they could have another long talk about the dangers of the younger brother's current hobby.

After about 15 minutes, Tadashi realized how bored he had become when his mind had wandered into less than innocent territory. It was then that he decided to mess with his little brother for a bit of entertainment.

He shifted, sliding a hand beneath his blanket as he chuckled to himself. If the mic wasn't on, he had no doubt that it'd be on soon, if only for confirmation, as he made small jerking motions with his hand. As an added effect, he changed his breathing to what he thought would give the impression that he was masturbating. If he was convincing enough he expected the camera's light to flicker off and he'd be free of its silent gaze.

But the light never faded.

Several emotions passed over his features and, even in the brightest room, the look that ended up on Tadashi's face would have been unreadable. In a matter of seconds, his mind had thought its way through several reasons on why the light hadn't gone off. None of which had hit him as hard as the thought that Hiro- his little brother, might still be watching him.

_Intentionally._

The thought alone had him harder than he'd ever been in his entire life and a low groan escaped from him before he could muffle it. He quickly lost the battle of guilt and desire, surrendering himself to sheer unadulterated need. 

Throwing off the covers, Tadashi wrapped his fingers around his cock and shivered at the much needed contact. After a few rough strokes he reached into his nightstand to retrieve the lotion he kept there. Once his fingers were coated with the creamy liquid he tossed the bottle to the foot of the bed and returned his attention to his dick. The lotion was cold compared to the warm flesh of his length and he let out a soft whimper, shuddering at the difference.

He tried to hold in the sounds of his pleasure, covering his mouth with his free hand as he began to pump his dick.

Then his mind was imagining his little brother standing before him, warm toffee eyes roaming over his exposed skin. That cute gap between fantasy Hiro's teeth revealed itself as he grinned and bit his bottom lip seductively. He spurred Tadashi on, never moving from his place at the foot of the bed as he whispered praises and directions that the elder brother obeyed without hesitation. 

_'Let me hear you nii-san,'_ fantasy Hiro begged and Tadashi let out a low moan as his hand fell from his mouth.

 _'That's it Dashi. Don't neglect the tip.'_ His fingers slid up his length and he swirled his thumb over the head, his precum mixing with the lotion.

The sounds poured from his lips as fantasy Hiro directed his actions. 

_'Not so quick Dashi, don't wanna end the show early now.'_

_'Such a good nii-san. Does it feel good?'_

_'Just like that, yeah.'_

He felt himself reaching the brink, his body covered in a sheen of sweat from his efforts, when his fictitious little brother clicked his tongue at him. Raising his head, he watched fantasy Hiro approach. Imaginary hands reached out, unreal fingers running through his hair, and he leaned into the make believe touch. Beneath the mix of pleasure and guilt he felt a pang of longing in his heart.

 _'What's wrong Dashi? I'm right here,'_ fantasy Hiro cooed, a soft look of understanding on his face.

"H-Hiro," he whispered to the empty room. 

The yearning of his heart broke through, shattering the fantasy. Despite the sinking feeling in his chest he willed his hand to stoke himself to completion. Grabbing a fist full of his comforter. he held it to his mouth to stifle his cry.

He remained still for a few moments waiting for the haze of bliss to clear from his mind, the evidence of his act present on his stomach and hand. A tiny light, unnoticed by Tadashi, faded to darkness as he thought to himself. He couldn't believe what he'd done. He was always extra careful _not_ to do that kind of thing around his brother. He had worked so hard to reign in his desires, to never reveal even a hint of his true feelings. And now he'd thrown it all away for a quick fix. Hiro may have only been fourteen, but his brilliant mind would have no trouble finding the right conclusion.

He had to be the worst big brother ever. 

Wiping the sweat from his face with his comforter, Tadashi shifted to sit on the side of his bed. He made quick work of cleaning himself off with the shirt he'd worn earlier. He'd wash it and his bedding tomorrow. He ran a hand through his, tugging on his fringe before glancing over his shoulder at the screen that separated his side of the room from Hiro's. The younger Hamada had to know it was open, and Tadashi hoped that if he closed it his brother would take it as a sign to leave it be. At least for now.

With a heavy sigh, he pushed himself up and padded across the floor to close it before returning to his bed. He settled in, throwing his comforter over himself haphazardly and tried not to over think things.

Maybe, if he was lucky, his secret would remain a secret regardless of his stupid libido.

**Author's Note:**

> Thank you for reading! Feel free to comment and let me know what you guys think!


End file.
